How to put all recipients of an alert into same SMTP envelop


What is the best way to get all contacts that receive a given notification into the To:
field (everyone in the same SMTP envelope / message)? After looking through the docs, $CONTACTGROUPMEMBERS doesn’t seem to do what I need.
Additionally, Nagios seems geared towards firing off a command per contact.
So if you’ve got 10 contacts receiving a notification, the notify-by-email (or whatever)
command gets run for each contact. (Maybe I’m understanding that wrong.)

What we’d like to achieve at our company is the following functionality:

Person A, B, and C, are all set to receive a specific notification. (trivial)
Person A, B, and C can all log in using their Nagios account to acknowledge the alert /
put into maintenance. (the default behavior once the above is set up)
Per notification, ONE email is sent out containing person A, B, and C all in the To: field.

Any ideas that aren’t an ugly work-around hack? Here’s the best I can come up
with so far, and it won’t work…

Create an Exchange distribution group for Person A, B, and C above.
For the notification in question, have FOUR Nagios contacts set up to receive
the notification: Person A, B, C, and the Exchange dist. group (created as a separate
contact in Nagios.)

Then, set up Person A, B, and C to have notifications globally disabled.
So the Exchange group gets the mail, everyone can Reply-All. BUT, Person A, B, and
C can still individually log in and acknowledge alerts.

But of course, this has the problem that if we ever want to send specific notifications
to Person B (for example), we’re out of luck since we disabled their notifications globally.

So yeah, I just can’t come up with a way to get what I need. Any help is appreciated.

P.S. Giving Person A, B, and / or C universal rights to view services and / or run commands is an unacceptable solution.